This invention relates to devices for loosening and tightening the lids on jars.
Loosening and removing jar lids is sometimes very difficult. Jars are often vacuum packed and the lids are tightened by mechanical means. This increases the amount of rotational force required to loosen the lids to remove the contents of the jars. Further, at times, the contents of the jars are viscous, so that the contents harden between the surface at the top of the jar and the inner surfaces of the lid. This condition often occurs with heavy, tacky materials such as honey or molasses, as well as other foods which can dry up.
People with reduced strength including children, the elderly, women and the ill and infirm sometimes require assistence to loosen and remove the lids on jars. Even strong individuals sometimes require help when lids are held fast by dried materials or when the lids have been strongly tightened by mechanical means at the factory. Further, persons with arthritic hands can neither grip the jar or the lid, so that even devices to assist in the loosening of lids are not helpful if the lid or jar be must gripped and held fast.
In addition to loosening the lids on jars to obtain the contents of the jars, it is often desireable to securely tighten the lids. Tightly closing containers with volatile materials is often required to prevent evaporation or the escape of noxious odors. Also, certain materials may be contaminated by oxygen or other outside elements if the jars or containers which are holding the materials are not tightly closed.
Existing devices to loosen lids on jars include those which have a circumferential section geared to a centrally located handle. The device is held above the lid to be loosened with the circumferential section of the device positioned outside of the circumferential rim of the lid. As the handle is rotated counter-clockwise the gearing causes the circumferential section of the device to tighten about the rim of the lid. Further counter-clockwise rotation of the handle while the jar is held tends to rotate the lid counter-clockwise and loosen the lid. The mechanical advantage created by the device, i.e. the force applied to the lid is greater than that applied to the handle, assists the user in loosening the lid. This type of device is fairly expensive to manufacture. It cannot be used to tighten lids and can only be applied to a limited range of lid sizes.
Another lid loosening device is installed under a counter top. The lid of the jar is slid into the device with the lid between a gnurled knob protruding downward from the surface of the device and an arcuate rim on the device. When the jar is grasped and turned, the device acts like a vise and the lid to loosened. However, the lid cannot be tightened by use of the device.
Matti, in U.S. Pat. No. 3,678,788 discloses a container top opener which comprises a looped strap connected near one end of a handle. When the the strap is placed around a lid adjacent the near end of the handle a larger lid may be loosened by rotating the handle about a fulcrum at the near end. When the strap is looped about a lid at the far end of the handle a smaller lid may loosened. The use of two devices, one with strap about the lid and the other with strap about the container is also disclosed.
This device, although useful for loosening lids of jars, has several shortcomings. First, the range of lid sizes and container sizes which can handle by the device is limited, because the strap loop is of fixed length. Further, the device is difficult to use. One hand must grasp the handle while the other holds the strap about the lid. After the slack in the strap is taken up by rotating the handle, the hand holding the strap is slipped down to grasp the jar and the handle may then be rotated further to loosen the lid. Although the use of two devices is disclosed, this would be difficult, if not impossible, to do, with people of ordinary dexterity. Also, for small metal lids, the strap inner surface generally slips rather than hold firmly to the lid.